en_tn/pro/28/13.md

hides his sins

"covers his sins." This is the opposite of confessing and forsaking sins, and is spoken of as covering sins rather than bringing them into the open (See: rc://en/ta/man/jit/figs-metaphor)

will not prosper

"will not succeed" or "will not advance"

the one who confesses them and abandons them will be shown mercy

This can be stated in active form. Alternate translation: "God will show mercy to the one who confesses and forsakes them" (See: rc://en/ta/man/jit/figs-activepassive)